Mechanical seals have long been known and used for forming a seal between a rotating shaft and a housing through which the shaft extends. Typically, a carbon seal washer is mounted to rotate on the rotating shaft and to slidably engage a seal seat mounted in the housing. The sliding engagement between the carbon seal washer and the seat forms a fluid-tight seal that, in conjunction with additional stationary seals, is operable to complete a fluid-tight seal between the shaft and the housing.
Often a plurality of coil springs are provided to force the carbon seal washer against the seal seat on the housing. In this assembly, the carbon seal washer is continuously urged along the shaft toward the seal seat so that the washer and the seat are maintained in a firm engagement even after both have been used for long periods of time.
However, problems have been encountered with the use of mechanical seals having coil spring forced carbon seal washers. Conventional mechanical seals utilizing a multiple coil spring arrangement often utilize coil springs mounted in a recess in the seal housing. The coil springs located in such recesses are susceptible to fouling and clogging by suspended particles and the like. The fouling of the springs may cause the seal to malfunction.
Further, in the assembly of a mechanical seal utilizing a multiple coil spring arrangement, usually, each individual spring must be properly positioned in the mechanical seal housing, and then the carbon seal washer must be forced into the seal against the spring force. Finally, some measure must be taken to retain the carbon seal washer within the seal housing resisting the spring force. This assembly procedure has proved difficult, and installation of such seal was often cumbersome. Mechanical seals of this type are generally expensive to manufacture.